The present invention relates to the field of automatic performance analysis and capacity planning and, more specifically, to the field of automatic performance analysis and capacity planning of computer systems which have been modified in response to interactive operator input.
Performance analysis in computer systems is used to determine the effectiveness and efficiency of a computer system's management of its workloads. The term "workload" refers to processes running on a computer system. Different types of processes are often treated as different workloads. For example, word processing is often considered as one workload even though several computer system users are operating word processing programs. Similarly, spreadsheets could be considered as a distinct workload.
Each workload requires system resources, such as CPU (central processing unit) processing time or disk capacity. Performance analysis is designed to facilitate the management of such system resources.
In carrying out performance analysis, one must always measure some values for computer system and component parameters in order to determine efficiency and efficacy. The parameter being measured have been referred to as "metrics." Examples of metrics are the number of cache in a particular time period, or the length of a device's queue. Metrics are discussed more fully in U.S. Pat. No. 4,849,879 to Chinnaswamy et al., which is incorporated herein by reference.
The metrics reflect the performance of the computer system in a particular configuration. The term "configuration" is used to refer not only to the types and interconnection of physical components, but also to the distribution of the workloads among the components.
Most conventional methods of performance analysis and capacity planning involve presenting selected information in reports. The reports are usually tabular presentations of data. Usually several different kinds of reports are needed for analysis. For example, one report might indicate the system configuration in terms of components, another report might indicate the system configuration in terms of workload, and another report may list certain metrics of interest.
One performance analysis and capacity planning product which generates tabular reports is the DECcp or DEC Capacity Planner for VMS made available by Digital Equipment Corporation for use with certain VAX computers. This product collects, reduces, analyzes, models and reports data in a tabular format for purposes of computer system capacity planning. Another such product is the VAX Performance Advisor made available by Digital Equipment Corporation to provide information useful in analyzing the performance of certain VAX computers.
Although the tabular presentation of data may be acceptable for determining the performance of a computer system in one configuration, it does not lend itself well to analyzing the performance of the computer system if its configuration were modified. Such analysis is important in determining whether and how to reconfigure a system.
For example, if performance analysis indicated an overload or bottleneck condition in a computer system, the system should be tuned or reconfigured to alleviate such conditions. It is not always apparent, however, which tuning or reconfiguration is the most appropriate. Physical reconfiguration of a system without knowing whether that reconfiguration will be effective is both impractical and costly.
To avoid unnecessary or incorrect reconfiguration, system engineers try to construct a model based upon actual system parameters. In this way, modeling may be used to measure the impact of certain actions on system performance before physically reconfiguring a computer system.
Modeling can also be used in sales. If a modeling technique were not too cumbersome, salespeople could use it to determine whether additional components were needed for a particular customer, or whether a customer's problems or needs could be handled in other ways.
Conventional performance analysis systems, however, do not lend themselves well to such uses. A common means of performing modeling involves using the information gathered as part of the performance analysis to calculate the effect of reconfiguring a computer system. This is both time consuming and inaccurate.
Systems such as the DECcp system will perform certain automated calculations, however, the calculations are presented in a tabular format, which may again require the use of several sheets or tables to analyze results.
It is therefore desirable to provide a mechanism for performance analysis that allows for a more meaningful presentation of performance information.
Another desire is to provide an improved mechanism for changing the configurations of the computer system, at least in a virtual sense, to determine the effects of such changes.
An additional desire would be to provide an improved mechanism for presenting the effects of the changes in configuration in a manner which allows ready decision making.
Additional advantages of this invention will be set forth in part in the description which follows and in part will be obvious from that description, or may be learned by practice of this invention. The advantages of this invention may be realized and attained by means of the instrumentalities and combinations particularly pointed in the appended claims.